The present invention relates to an industrial robot with an upper robot arm according to the type described in the introduction to claim 1. The present invention also relates to guiding device for a cable set for an industrial robot with a rotatable robot arm and to a use of the guiding device for a cable set for an industrial robot with a rotatable robot arm.
It has been common to draw cable sets for industrial robots on the outside. However, during recent years, it has become more common to try and draw the cable set within the robot. This protects the cables from damage and breakage and avoids loose cables getting in the way in the working area around the robot.
In a hollow elongated rotatable robot arm, it is previously known to draw two cable sets, normally a power cable and a signal cable. Drawing additional cables internally, bulky and stiff cables, for example, has been regarded as difficult and as significantly restricting the rotational movement of the robot arm. The cable set described below refers to one or more cables and/or lines for electricity, fluids, other media, etc. and can even refer to empty flexible protective coverings inside of which one or more lines or cables can be arranged.
It has been previously known to only arrange separate holders for individual cable sets, cables or lines. However, separate holders do not allow the introduction of a whole cable set that is complete from the foot of the robot up to the upper arm of the robot and that can be drawn within the robot. Neither does the use of separate holders in the arm of the robot allow the use of additional more rigid cable sets for pressurised air, welding etc. as the movement of rotation of the robot arm is restricted. The use of separate holders for each cable set makes it difficult to efficiently fit and replace cable sets. It is thus important to be able to quickly and simply introduce and remove cable sets in the robot.
A further problem that arises when cable sets are drawn internally is that the component lines wear against one another and against the inner walls of the robot arm during long periods of use.
It has hitherto been considered to be necessary to arrange the cable sets in swivel or spiral forms. In this respect, however, the movement of rotation of the robot arm has in practice been restricted to a maximum of +/xe2x88x92250xc2x0. With a rotation of the robot arm as named below, it is considered that the robot arm also performs a movement of rotation. In addition, spiral formed cables are bulky, costly, complicated and have a relatively short working life.
The general design of an industrial robot with a rotatable upper robot arm of the type named here can have the appearance of the construction design described in U.S. Pat. No. 5,564,312.
An industrial robot with a rotatable upper robot arm is previously known from SE-A-9004150. Here a cable set that extends through the robot arm is attached in two holders arranged around the axis of rotation at an axial distance from one another.
The present invention aims to minimise the disadvantages named above according to the prior art. The aim of the present invention is thus, among other things, to achieve a cable set that can be drawn internally within a robot arm of an industrial robot where the cable set withstands the mechanical stresses to which it is exposed during the rotation movement of the robot arm. In addition the intention is to achieve a cable set arrangement that is simple and cost effective and that is easy to fit and/or replace as well as repair.
The solution is found with an industrial robot with the features stated in claim 1. More specifically, according to claim 1, the present invention relates to an industrial robot with an upper robot arm that comprises a first arm part arranged to rotate around its own longitudinal direction at a second arm part, whereby the cable set extends through both arm parts, whereby a guiding device for the cable set is arranged at the upper robot arm, where the guiding device comprises through cavities arranged to guide at least one line within it in a sideways direction and to allow the displacement of at least one line within it in a longitudinal direction. One advantage of this is that the cable set is allowed to perform a relatively large rotational movement without the cable set getting entangled or without damage or a bad contact arising. This ensures a long working life for the cable set. Due to the present invention, a means of simply and efficiently replacing the cable set is also achieved. A further advantage is that different users of industrial robots can quickly and easily install a cable set of their choice, e.g. welding cables, tool cables, water piping or a pressurised air line.
The present invention also comprises a guiding device for a cable set for an industrial robot with a rotatable robot arm, whereby the guiding device for the cable set comprises a plate for guiding the cable set with ring-shaped cavities and a holder for the plate for guiding the cable set.
With the guiding device for a cable set according to the present invention, the rotating arm part can display a movement of rotation up to at least +/xe2x88x92300xc2x0 without the cable becoming entangled and without bad contact or wear of the cable set arising.
When the robot arm is turned or rotated to its furthest end position, e.g. 300xc2x0 or more in any direction, the cable set is, as a consequence, thus fully extended. During a movement of rotation of the robot, therefore, it is necessary that the cable set is slack at the initial starting position of the robot arm. In this respect, the cable set can be slack in that part of the cable set that is inside and/or outside the upper arm of the robot. Slack means that a part of the cable set can hang freely and not be under tension. A cylinder for surrounding the cable set can even be suitable to arrange centrally in the robot arm around the axis of rotation with the aim of supporting a slack cable set.
The guiding device, comprising the plate for guiding the cable set with ring-shaped cavities and the holder for the plate for guiding the cable set, is preferably disk-shape designed. The guiding device can be executed in a material of one""s own discretion, such as metal sheet plate, aluminum or plastic.
The plate for guiding the cable set is preferably provided with a central cavity intended, for example, for a bulky and rigid cable set such as a pressurised air line or a welding cable. According to the invention, the described industrial robot, which can also be termed a manipulator with a guiding device, is of a type intended to support weights of at least 50-60 kg.
The present invention also relates to a use of the said guiding device for an industrial robot with a rotatable robot arm. In this respect, the use of a guiding device for the cable set at the upper robot arm is suitably to guide at least one line within it in a sideways direction and to allow the displacement of at least one line within it in a longitudinal direction.